SEOUL, April 9 (Yonhap) -- Ahead of a summit with North Korea, South Korea is exploring ways to improve inter-Korean relations to a sustainable level and develop them even under international sanctions, Seoul's point man on the North said Monday.

Unification Minister Cho Myoung-gyon made the remark as President Moon Jae-in and North Korean leader Kim Jong-un prepare to hold a summit on April 27 on the southern side of the border truce village.

The two sides are expected to discuss ways to denuclearize North Korea, bring permanent peace to the Korean Peninsula and improve inter-Korean ties.

"One issue is how to institutionalize sustainable inter-Korean relations. The other is what can be done under the sanctions regime (to develop ties)," Cho told reporters when asked about possible agenda items in terms of inter-Korean ties.

The upcoming summit will be a key venue to discuss the North's denuclearization ahead of Kim's proposed meeting with U.S. President Donald Trump, which could take place by May.

When the two Koreas previously held summits in Pyongyang in 2000 and 2007, they unveiled landmark joint declarations on inter-Korean relations and reconciliation that also included ways to boost economic cooperation.

But Seoul cannot provide massive economic benefits to North Korea as international sanctions target curbing inflows of hard currency to the regime out of concerns over its nuclear and missile programs.

The minister also said Kim Yong-chol, a top North Korean official in charge of inter-Korean affairs, appears to be playing a key role even with respect to North Korea's nuclear issue and diplomacy.

Kim, a vice chairman of the central committee of the ruling Workers' Party of Korea (WPK), visited South Korea in February as the head of the North's high-level delegation to the closing ceremony of the PyeongChang Winter Olympics. He also accompanied Kim Jong-un on his latest trip to China.

Cho said that, given that Kim sat closer to the North's ruler at the North-China summit than top diplomat Ri Yong-ho and Ri Su-yong, a vice party chairman in charge of international affairs, his clout seems to extend beyond inter-Korean affairs.